The so-called 30-10 plan seeks to reduce construction times up to 20 years for a dozen transit projects, including the Westside subway extension, that were approved when voters passed Measure R.

Stepping into uncharted territory, the Metropolitan Transportation Authority on Thursday unanimously endorsed Los Angeles Mayor Antonio Villaraigosa's ambitious plan to accelerate billions of dollars in transit projects with help from a federal assistance program that is still on the drawing board.

The so-called 30-10 plan seeks to reduce construction times up to 20 years for a dozen transit projects, including the Westside subway extension, that were approved when voters passed Measure R, the half-cent sales tax that promised to deliver $40 billion in transportation improvements in Los Angeles County.

The MTA board also agreed to fast-track a variety of highway projects contained in the measure, such as improvements to Interstate 5, the controversial northern extension of the Long Beach Freeway and construction of the high desert corridor from the Antelope Valley Freeway to Interstate 15.

MTA's support for expediting key transportation projects clears the way for future lobbying in the nation's capital and continued efforts to create a unique funding mechanism for the 30-10 plan.

"This has never been done," said Villaraigosa, who sits on the MTA board, "and I'm not sure we can say with a straight face that it will be done. But when you see unemployment as high as 14%, when you see the dirty air and its health consequences, and when you see the opportunity to create 166,000 jobs over 10 years, we have to do something."

The 30-10 plan is unprecedented because it seeks to create a pool of federal money to speed construction of light rail, subway and rapid transit bus projects. The idea has gained some traction in Congress and the U.S. Department of Transportation.

Under such a program, it might be possible for the nation's third-largest transportation agency to borrow federal money and pay it back with Measure R revenue or secure loan guarantees, which would allow the MTA to finance transit projects with bonds sold to investors.

Agency officials said, however, that they would try to accelerate road projects with public-private partnerships and funding from more traditional federal highway programs.

If successful, the accelerated projects could be done within 10 years — far faster than the 30-year time frame spelled out in Measure R for many of the proposals. The public would benefit sooner, MTA officials say, from improved air quality, less traffic congestion, reduced fuel consumption and more transportation options.

"We have a chance to do something unprecedented that could profoundly change the quality of life in Los Angeles County," said Richard Katz, an MTA board member.

Among the 12 transit projects in the 30-10 plan are the regional connector for light rail in downtown Los Angeles, the Foothill Extension of the Metro Gold Line, a Green Line extension to Los Angeles International Airport and the South Bay, the Crenshaw corridor transit project, and the Orange Line Canoga Extension. The estimated cost of all the projects is about $20 billion.

The motion to expedite highway projects was offered by two board members, Lakewood City Councilwoman Diane Dubois and Santa Monica City Councilwoman Pam O'Connor. Some cities in Los Angeles County were concerned that they would not benefit from the 30-10 plan and wanted highway improvements in their areas expedited.

County Supervisors Michael D. Antonovich and Mark Ridley-Thomas made the motion to add public-private partnerships as a possible source of funding for highway and transit projects. They also pushed to ensure that the 30-10 plan reflected priorities in the county's long-range transportation plan, such as the Foothill Gold Line extension to Claremont and the Crenshaw/LAX light rail corridor.